If you charge your Delhi Metro Card with a Credit Card, you will be charged ~1% convenience fees. Some banks even charge 2%. You can try Amazon ICICI Pay Credit Card which will give similar cashback.
Alternatively you can go for ICICI Unfaire Metro Credit Card - it offers 10% off on Metro Fares and 1% off on Auto-top ups. It has an Annual Fees of 299 + GST
